I ran my waterfall to aerate the water to bring TA from 110 down to 80 since my CYA was at 80. I kept ph at 7.0 to 7.2 to speed up the muriatic acid process of lowering TA. Boy, did my TA drop. The final number was 60 TA, calcium also drop to 240. Over the summer calcium went from 300 to mostly 400, then 420 about a week ago prior to aeration. From what I read, calcium is like CYA in that unless you're doing a water change, it shouldn't really change.
I did add in 9 boxes of Borax with Muriatic per site's instructions but I don't think that should have any effect on CH, right?